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Jan. 31, 1956 c MUSSER 2,732,897

ND APPARATUS METHOD OF A PERFORATING HOLLOW OBJE Filed June '7, 1951 2Sheets-Sheet l 5 way!!! ii'l7ii \1 \\o\\ llllllzllll In [ll-l lF'ZTFITFIIEFAMIH III! IIIIIJIHIL';

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INVENTOR. G WALTON MUSSER ATTORNEYS Jan. 31, 1956 c 'w. MUSSER 2,732,897METHOD OF AND APPARATUS PERFORATING HOLLOW OBJE Filed June '7, 1951 2Sheets-Sheet 2 III 9 III /IIH INVENTOR. C WALTON MUSSER ATTORNEYS=METHOD OF AND APPARATUS FOR PERFORAT- lNG HOLLOW OBJECTS C WaltonMusser, Philadelphia, Pa.

Application June 7, 1951, Serial No. 230,360

6 Claims. (Cl. 16490) (Granted under Title 35, U. S. Code (1952.), see.266) The invention described in the specification and claims may bemanufactured and used by or for the Government for governmental purposeswithout the payment to me of any royalty thereon.

This invention relates broadly to the art of perforating hollow objectsand, while-not limited solely thereto, has special reference toperforating the tapered, cylindrical cartridge case wall of ammunitionused in some 7 recoiless firearms.

quickly and satisfactorily accomplishing the perforating operation.

Those skilled in the mechanical arts realize that such work could bedone in a variety of well-known ways employing a drill press, punchpress, or similar type machine tool. However, such processes, if donewith minimum conventional equipment, would be too slow; and, if donewith maximum conventional equipment, Would be too costly. Now, by meansof my inventive method and apparatus, the perforating of cartridgecases, as well as numerous other objects, can be accomplished bothquickly andeconomically, thus offsetting the disadvantages of existingprior art means.

My invention contemplates the use of rapidly applied, confined hydraulicor pneumatic pressure (applied either from inside or outside the objectto be perforated) to accomplish multiple perforation of the objects wallin a substantially simultaneous manner.

In one form of my invention in which is used hydraulic pressure appliedfrom inside the cartridge case, the cartridge case or other hollowobject to be perforated is placed in a close-fitting sleeve or diefixture from which protrudes the cases head, or grooved end. The wall ofthe sleeve has accurately shaped and located openings therethrough whichare arranged in the pattern it is desired to produce in the sidewall ofthe cartridge case. The sleeve, in turn, is placed in a closefittingsupport block. A plunger is provided which slidably fits the mouth endof both the sleeve and the cartridge case in a substantiallyliquid-tight, piston-cylinder relationship. This plunger is designed sothat a certain length thereof will always project from the mouth end ofthe sleeve a predetermined distance. Confined between the inner end ofthe plunger and the closed, head end of the cartridge case is a body ofhydraulic fluid.

To perforate the cartridge case sidewall, pressure, preferably in theform of a sharp impact, such as that supplied by a drop hammer, isexerted upon the plunger nited States Patent ice and the resultant forceis transmitted to the body of hydraulic fluid. Because of the closenessof fit between the plunger and the sleeve, between the plunger and v thecartridge case, between the cartridge case and the sleeve, and betweenthe sleeve and the support block, and, further, because of the rapidityof action of the impact force, there is negligible, if any, leakage ofthe hydraulic fluid. When the pressure is great enough, those parts ofthe cases sidewall which are unsupported, because of the openingsthrough the sleeve, are therefore punched out through those openings byone stroke of the plunger. In other words, the well-known punchand-dieaction is simulated with the sleeve serving as the die while the role ofthe punch is einciently assumed by the trapped hydraulic fluid underimpact pressure. In this manner, the openings through the wall of thesleeve are reproduced in exact size and pattern through the wall of thecartridge case.

In another form of my invention in which is used pneumatic pressureapplied from inside the cartridge case, an explosive powder issubstituted for the hydraulic fluid, and the support means is fittedwith a primer and a detonating means therefor. Subsequent ignition ofthe explosive powder generates sufficient force within the cartridgecase to cause its perforation in a manner similar to that describedabove.

In cases where the shape of the object to be perforated lends itself tothe insertion and removal of a mandrel, or like member, other forms ofmy invention are used in which the rapidly applied hydraulic orpneumatic pressure required to perforate the object is applied fromoutside the object, rather than from the inside as previously described.1

in using externally applied hydraulic pressure, the object to beperforated is placed over a close-fitting die fixture having therequired size, shape, and pattern of openings it is desired to duplicatein the wall of the object. The die fixture is then slidably positionedon a post which is secured, as by threads, in a container. The containernext is filled with the necessary amount of a hydraulic fluid which isthen subjected to a selected pressure from a plunger fitting inside thecontainer in fluid-tight relationship. As before, those portions of theobjects Wall which are unsupported by the die fixture are perforated inaccordance with the size, shape, and pattern of the openings in the diefixture.

In another form of my invention whereby I contemplate the use of anexternally applied pneumatic pressure to perforate the wall of thehollow object, the object to be perforated is placed over aclose-fitting die fixture having the required size, shape, and patternof openings desired in the wall'of the object. The die fixture is thenslidably positioned on a post secured in the container. An explosivecharge is placed in the container outside the object to be perforated,and the container is closed tightly by a lid which contains a primermechanism. When the primer is detonated, in any convenient manner, itsfire ignites the explosive charge. The resulting gas pressure producedis sufficient to perforate the wall of the object in accordance with theopenings in the die fixture.

Having described the general purposes of my invention, and the means foraccomplishing them, I will now discuss them in more specific detail.

One object of my invention is to provide a means for completely andsimultaneously perforating a number of round or other shaped holesthrough the walls of cylindrical, or other shaped work pieces.

Another object is to provide a method of simultaneouslymulti-perforating cylindrical, or other objects,

Yet another object is to provide a method of simultaneouslymulti-perforating cylindrical, or other objects, which utilizes pressureresulting from the ignition of trapped explosive, or like material, tofurnish the shear ing force required.

A further object is to provide a punch and die type combination forperforating in which the force normally supplied by the punch element issupplied by hydraulic or pneumatic pressure applied from inside or fromoutside the object to be perforated.

The foregoing and other objects and advantages of my invention willbecome apparent from an inspection of the following description and theaccompanying drawings wherein:

Fig. 1 is a central, vertical section through one illustrative form ofmy inventive apparatus and a workpiece just prior to the perforationoperation. This figure shows how a hydraulic fluid positioned within theworkpiece may be adapted to furnish the pressure necessary to perforatethe workpiece;

Fig. 2 is a view of the workpiece, in the form of a cartridge case,after the perforations have been made and the case removed from the Fig.1 apparatus;

Fig. 3 is a modification of the Fig. l embodiment of my invention andshows how an explosive, or like material, positioned within theworkpiece may be employed to supply the pneumatic pressure necessary toperforate the workpiece;

Fig. 4 is a view of another form of my invention showing how a hydraulicfluid outside the workpiece may be employed to produce the pressurenecessary to perforate the workpiece; and

Fig. 5 is a modification of the Fig. 4 embodiment of my inventionshowing how an explosive, or like material, positioned outside theworkpiece may be employed to supply the pneumatic pressure necessary toperforate a workpiece.

Perforation by means of internally applied hydraulic pressure Fig. 1shows that one form of my novel apparatus consists of a tubular sleeve 6having concentric, axial recesses 7 and 8. Recess 7 is shaped toaccommodate the cartridge case 9 to be perforated in such a way that theclosed, head end 10 of the case projects somewhat beyond the adjacentend of the sleeve. In the wall of sleeve 6 are a plurality of accuratelysized and located openings 11 arranged in the pattern in which it isintended to perforate cartridge case 9. Sleeve 6 will be seen to haveclose fitting contact with case 9 and therefore supports the casesidewall at all places except where there are openings through thesleeve.

Recess 8 slidably accommodates a plunger 12 in liquidtight relationshipwith the sleeve. The plunger also has a similar slide fit, liquid-tightrelationship with the mouth end 13 of the cartridge case. As Fig. 1shows, the outer end of plunger 12 projects somewhat beyond the end ofsleeve 6.

Trapped between the plungers inner end and the cartridge cases closedhead end 10 is a body of hydraulic fluid 14 whose function will beexplained later.

Sleeve 6 bearing cartridge case 9 is matingly accommodated in a supportblock 15 in such a way that the cases head end 10 projects beyond theblocks base end 20. Thus, the wall of sleeve 6 is supported by block 15which possesses a sufficient amount of the bulk and strength neededsafely to withstand the pressure generated within the apparatus duringthe perforating operation.

My apparatus is, for purposes of illustration only, shown associatedwith the bolster plate 16 and the drop hammer 17 such as are commonlyemployed on a forging machine or like apparatus. Since such machines arewell known, only the named essential parts thereof are shown.

In the operation of this form of my invention, the cartridge case 9 tobe perforated is filled almost to its top with hydraulic fluid 14 andthen placed inside sleeve 6. The sleeve with its contained case is thenplaced in support block 15. The case, sleeve, and support block are thenplaced upon bolster plate 16 of the representative forging type machine.Plunger 12 is inserted into the sleeve and the aligned cartridge caseneck until it rests atop hydraulic fluid 14.

When the forging machine (not shown) is operated, hammer 17 approachesand strikes plunger 12. Impact energy from the moving hammer istransmitted, by means of the plunger, to the trapped hydraulic fluid 14.Because of the practically incompressible nature of the fluid, thepressure, in turn, is exerted against the sidewall of the cartridgecase. When the pressure is great enough, the wall portions of thecartridge case which are unsupported by the sleeve because of openings11 therein are punched out by the fluid. The punched-out slugs (notshown) are pushed by the hydraulic fluid through openings 11 in sleeve 6and against the unyielding support block 15.

It can easily be realized that with the proper amount of energy suppliedby the hammer, enough energy can be generated to perforate all the holesin the cartridge case by one stroke of hammer 17.

As hammer 17 ascends at the completion of the perforating operation, thefinished case A and the slugs (not shown) are removed from the apparatusand the operation is repeated. Fig. 2 shows the representative cartridgecase 9A after perforation by means of my novel method and apparatus.Holes 18 of required size, shape, and in proper location have beenproduced in the cases sidewall in conformity with the size and locationof openings 11 in sleeve 6.

Perforation by means of internally applied pneumatic pressure In orderto perforate the cartridge case by the means of an internally appliedpneumatic pressure, I provide the sleeve and support block arrangementreferred to above, but, in place of the hydraulic fluid, use is made ofan explosive material 23 (see Fig. 3). As there shown, the support block15A is provided with a lid 24. This lid contains a recess whichaccommodates a percussion primer 25 and a firing pin 26, and ispositioned atop support block 15A so that the primer is in alignmentwith the explosive charge contained within the cartridge case to beperforated. As Fig. 3 shows, the firing pin is constantly urged awayfrom the percussion primer by means of a coil spring 27 which exertspressure against a pin 28 transfixing the firing pin.

Lid 24 is urged in any convenient manner, as by pressure plate 29,against support block 15A so as to effect a sealing relationship betweenthat plateand the support block. To aid this sealing relationship, thecartridge case to be perforated rests upon a companion pressure plate16A.

In the operation of this form of my invention, a sharp blow from thehammer-like member 17A is delivered to the firing pin. The firing pin ismoved down to strike percussion primer 25. Fire from the primer ignitesthe main explosive charge 23 located within the cartridge case. Theforce generated by this ignition generates sufiicient pressure withinthe cartridge case to cause perforation of its sidewall in a mannersimilar to that already described.

Perforation by means of externally applied hydraulic pressureEmbodiments of my invention using externally applied hydraulic andpneumatic pressure are respectively shown in Figs. 4 and 5.

In the Fig. 4 embodiment, the object 38 to be perforated is placed overa close-fitting die fixture 32 having the required size, shape, andpattern of openings 33 which are to be duplicated in the wall .of object38. The die fixture'is then-slidably positioned on a post 34 which issecured, as by threads 35, in a container 36. The container is thenfilled the necessary amount with a hydraulic fluid 14A which is thensubjected to a selected impact pressure from a plunger 37 fitting insidethe container in fluid-tightrelationship. As before, those portions'ofthe objects wall which are unsupported by the die fixture will beperforated in accordance with the size, shape, and pattern of theopenings in the diefixture. Slugs (not shown) resulting from theperforating operation will be pushed into the openings in the diefixture from which they can subsequently be easily removed. "If theforce is applied with sufiicient rapidity, post .34 referred to in thisillustrative form of my invention may be eliminated, in which case thedie fixture would be secured to the container in any convenient manneras by threads (not shown). The fact that the die fixture is hollow wouldenable the slugs resulting from the perforating operation to be easilyremoved.

Perforation by means of externally applied pneumatic pressure in thisform of my invention (see Fig. the object 38A to be perforated is placedover a close-fitting die fixture 32A having the required size, shape,and location of openings 33A desired in the Wall of the object. The diefixture is then slidably positioned on post 34 secured in chamber 36,and an explosive charge 23A is placed in the chamber outside the objectto be perforated. The lid 24 and pressure plate 29 combination, earlierdescribed in connection with Fig. 3, is placed in sealing relationshipover chamber 36, and the explosive charge is' ignited, as earlierexplained, by hammer 17A striking firing pin 26. Gas pressure resultingfrom ignition of the explosive charge is sufficient to cause perforationof the wall of the object in conformity with openings 33A in die fixture32A. As mentioned above in connection with perforation by means ofexternally applied hydraulic pressure, post 34 in this embodiment couldalso be eliminated, if desired, and the die fixture secured to thecontainer.

Conclusions My inventive method of and apparatus for perforating, ofcourse, need not be restricted to use in the production of cartridgecases. Indeed, the application of my invention is'q-uite adaptable innumerous other instances. For example, it would be quite advantageous inperforating irregularly shaped objects, or objects in which the axes ofthe perforations were at random angles to tire object or to each other.Such cases may require the use of multiple sleeves, or of sleeves splitin the fashion of molds, but the principle herein disclosed wouldnevertheless be the same.

it is understandable, too, that means other than a forging, or similarmachine may be provided for quickly exerting the required force upon theplunger or firing pin. For example, the plunger or firing pin couldreceive energy generated by explosives or as a result of action similarto that found in the cylinder ofan internal combustion engine.

From the foregoing, it will be seen that I haveiprovided a means forcompletely and simultaneously perforating a number of round or othershapedv holes through the walls of hollow, cylindrical and other shapedworkpieces; that I have provided a method of simultaneouslymultiperforating cylindrical, and other objects, which utilizes pressureon a trapped fluid medium or pressure resulting from detonation of'atrapped explosive to furnish the shearing force required; and, that Ihave provided a punch and die type pombination for perforating in whichthe force normally supplied bythe punch element is supplied by hydraulicor pneumatic pressure applied from inside or fromoutsidethe object to beperforated.

The above description should make it obvious to those skilled in the artto which this invention relates, or to which it is most nearlyassociated, that many variations and modifications of 'my novel methodand apparatus could be made Without departing from their original spiritand scope. I, therefore, do not wish to be limited by the narrowconfines as presented by this merely illustrative presentation, butrather by the scope of the appended claims.

I claim:

1. Apparatus for perforating the wall of a hollow, substantiallyinelastic and non-flexible metallic object comprising a die fixture insnug fitting and relatively unyielding supporting relationship to theoutside surface of the wall of said object and having openings ofrequired size, shape and location, solid explosive means disposed withinsaid object in contact with the inner surface of the wall thereof, saidexplosive means filling a major portion of said object for use whenignited instantaneously to exert sufficient gaseous pressure directlyand with high velocity on said wall thereby to perforate said wall inconformity with the openings in said die fixture, and means to ignitesaid solid explosive means.

2. Apparatus for perforating the wall of a hollow, substantiallyinelastic and non-flexible metallic object comprising a die fixture insnug fitting and relatively unyieldingly supporting relation to one sideof the wall of said object and having openings of required size, shapeand location, means together with portions of the object providing aclosed chamber on the opposite side of the wall of the object adjacentto the area thereof to be perforatcd, solid explosive means disposedwithin and substantially filling said chamber for use when ignitedinstantaneously to exert sufficient gaseous pressure directly and withhigh velocity on said opposite side thereby to perforate the object inconformity with the openings in said die fixture, and means to ignitesaid solid explosive means.

3. In apparatus for perforating the sidewall of a hollow substantiallyinelastic and non-flexible metallic object, the objects sidewall havingan opening therethrough communicating with the hollow interior, thecombination of a sleeve fitting around and relatively unyieldinglysupporting the sidewall of said object and having lateral openings ofrequired size, shape and location, an explosive charge filling a majorportion of said hollow object adjacent the wall area to be perforated, alid sealing the opening into said hollow object, and primer means toignite said explosive charge thereby to generate suflicient pneumaticpressure within said hollow object so as to act with high velocity uponand thereby perforate its sidewall according to the size, shape andlocation of said lateral openings in said sleeve.

4. In perforating apparatus, the combination with a hollow,substantially inelastic and non-flexible metallic object of a sleevefitting around and relatively unyieldingly supporting the sidewall ofsaid object and having lateral openings of required size, shape andlocation, said sidewall having an opening therethrough communicatingwith the hollow interior of said object, an explosive charge filling amajor portion of said hollow object adjacent the wall to be perforated,a rigid support block surrounding and unyieldingly supporting thelateral surface of said sleeve, a lid fitting said support block andsealing the opening into said hollow object, a percussion primer in saidlid to ignite said explosive charge, a firing pin movably mounted insaid lid for detonating said percussion. primer, and a hammer instriking relation to said firing pin whereby to detonate said percussionprimer to cause ignition of said explosive charge and thereby togenerate sutficient pneumatic pressure within said hollow object so asto act with high velocity upon and thereby perforate its sidewallaccording to the lateral openings in said sleeve.

5. In apparatus for perforating the wall of a hollow, substantiallyinelastic and non-flexible metallic object by means of an externallyapplied pneumatic pressure, the combination of means providing a chamberand having an opening thereinto, a die fixture supported in said chamberfor snugly fitting the inside wall of the hollow object and havingrecesses therein of the size, shape and arrangement desired to beduplicated in the wall of the hollow object, an explosive charge fillinga major portion of said chamber and surrounding the hollow object, meanssealing said chamber means opening, and primer means for igniting saidexplosive charge, whereby sufiicient pneumatic pressure is generated inresponse to igniting said primer means and applied externally to thehollow object to perforate those portions of the hollow objects wall inaccordance with said die fixture openings.

6. In apparatus for perforating the wall of a hollow, substantiallyinelastic and non-flexible metallic object by means of an externallyapplied pneumatic pressure, the combination of a hollow container havingan opening through a wall thereof, a sleeve-like die fixture supportedwithin said container for snugly fitting the inside wall of the hollowobject and having openings therein of the size, shape and arrangementdesired to be duplicated in the wall of the hollow object, an explosivecharge filling a major portion of said container and sur rounding thehollow object, cover means on said container for sealing said containeropening, a percussion primer carried by said cover means for ignitingsaid explosive charge, and mechanical means carried by said cover meansdisposed for engagement with said percussion primer for detonationthereof, whereby ignition of said explosive charge will generate andapply sufl'icient pneumatic pressure externally to the hollow object andperforate the wall thereof in conformity with the openings in saidsleeve-like die fixture.

References Cited in the file of this patent UNITED STATES PATENTS Re.23,211 Mohaupt Mar. 21, 1950 1,275,462 Nickerson- Aug. 12, 19181,588,200 Skelton June 8, 1926 2,204,273 Hale June 11, 1940 2,233,930Witt Mar. 4, 1941 2,276,259 Temple Mar. 10, 1942 2,280,204 Tracy Apr.21, 1942 2,315,496 Boynton Apr. 6, 1943 2,326,536 Hartsock Aug. 10, 19432,362,829 Kinley Nov. 14, 1944 2,395,123 Hutt Feb. 19, 1946 2,405,714Ryan Aug. 13, 1946 2,422,900 Hubalek June 24, 1947 2,467,034 Hutt Apr.12, 1949

